Cysts Flashcards
What is the definition of a cyst
pathological cavity which contains fluid, semifluid or gaseous content and is not created by the accumulation of pus
What are the signs/symptoms of cysts
possibly swelling
impeded eruption
often asymptomatic unless infected
What is the first line x-ray for a cyst
periapical
When may OPT/occlusal be taken for a cyst
When the cyst is too large to be captured fully in a periapical
What supplemental views may be taken in addition to plain film x-ray
CBCT/facial radiographs e.g PA mandible/occipitomental
What radiographic features should be noted in a report when reporting on a cyst
location
shape
margins
locularity
multiplicity
effect on surrounding anatomy
What may a lack of margins be indicative of
infection
lack of corticated margin
What are cysts classified based on
structure
origin
pathogenesis
How can cysts be classified by structure
epithelial lined vs non epithelial lined
How can cysts be classified by origin
odontogenic
non-odontogenic
How can cysts be classified by pathogenesis
developmental
inflammatory
What can odontogenic cysts be split into
developmental and inflammatory
What are the main developmental odontogenic cysts
dentigerous (& eruption cysts)
odontogenic keratocyst
Lateral periodontal cyst
What are the main inflammatory odontogenic cysts
radicular cyst (& residual cyst)
inflammatory collateral cysts
What are the two types of inflammatory collateral cysts
paradental cyst
buccal bifurcation cyst
What is an example of non-odontogenic developmental cyst
nasopalatine duct cyst
What is an example of other non-odontogenic cyst
unknown cause
solitary bone cyst
aneurysmal bone cyst
What is unique solitary bone cyst and aneurysmal bone cyst
both have no epithelial lining
What is the most common odontogenic cyst
radicular
What are some features of odontogenic cysts
- found in tooth bearing areas
- all epithelial lined
- most common cause of bony swellings in the jaw
Where can the odontogenic cyst epithelial lining originate from
rests of mallasez
rests of serres
reduced enamel epithelium
What is a radicular cyst
it is an inflammatory odontogenic cyst
Why are sensibility testing important in diagnosis for radicular cyst
- the tooth must be non vital
How does a radicular cyst form from a non-vital tooth
non-vital tooth forms chronic apical infection
chronic apical infection results in periapical granuloma (progression from acute apical abscess/chronic sinus/acute apical periodontitis)
then progresses to radicular cyst
When measuring the size of the radiolucency on the x-ray, what measurement would point to a radicular cyst rather than a PA granuloma
> 15mm
indicative of a radicular cyst
What are the radiographic features of a radicular cyst
well defined
round/oval
corticated margin is continuous with the lamina dura
larger lesions may displace adjacent structures
What can a long standing radicular cyst result in
external root resorption
contain dystrophic calcification
What is dystrophic calcification
can occur in longstanding radicular cysts
this is the deposition of calcium salt in degenerated tissues in the absence of systemic mineral imbalance
What type of epithelium is found in the epithelial lining of a radicular cyst
non keranizied stratified squamous
variable thickness
What cystic features can be seen on the histopathology for radicular cyst
- epithelial lining (often incomplete)
- connective tissue capsule
Where do the cells of a radicular cyst originate from
rests of mallasez
On a histological level, how does radicular cyst form
- rests of mallasez scells proliferate in the peri-apical granuloma, when this happens the centre of the granuloma is cut off from the blood supply resulting in central necrosis
- may also form by epithelium surrounding the fluid filled area
What type of growth do we usually see in radicular cysts
unicentric balloon type growth
How do radicular cysts continue growth
histology
centre of the cyst draws in water from the surrounding areas by osmosis and puts pressure on surrounding bone resulting in resorption
inflammation results in release of inflammatory mediators which increases the cyst size
What are the key histological features that are distinct in radicular cysts
- variable inflammation
- cholesterol clefts
- mucous metaplasia
- hyaline/rushton bodies
What are cholesterol clefts
radicular cysts
- derived from breakdown of RBC as a result of haemorrhage
- may be few in number or form large mural nodules
- usually associated with epithelial discontinuities and project into the cyst lumen
- cholesterol crystals may be found in the cyst fluid
What are hyaline/rushton bodies
radicular cysts
found in the epithelial lining
appear as eosinophilic bodies of varying size and shape
of unknown origin
What are the 2 variants of radicular cyst
- residual cyst
- lateral radicular cyst
What are residual cysts
radicular cysts
this is when a residual cyst persists after loss of the tooth/post-RCT (if successful)
What are lateral radicular cysts
radicular cysts
*radicular cysts are associated with lateral canals
located at the side of the tooth rather than the apex
What type of cyst is an inflammatory collateral cyst
inflammatory odontogenic cyst
What is an inflammatory collateral cyst associated with
vital tooth
What are the two main types of inflammatory collateral cysts
paradental cyst
buccal bifurcation cyst
What is a paradental cyst
typically occurs at the distal aspect of partially erupted third molars
What is a buccal bifurcation cyst
typically occurs at the buccal aspect of the mandibular firs tmolar
crown of the tooth will start to tilt buccally
What type of cyst is a dentigerous cyst
developmental odontogenic cyst
What type of cyst is a dentigerous cyst
developmental odontogenic cysts
What is a dentigerous cyst associated with
crown of unerupted tooth and usually impacted tooth
What is the dentigerous cyst derived from
cystic change of the dental follicle
What are the radiographic features of a dentigerous cyst
corticated margin attached to CEJ of the tooth
may displace involved tooth
tends to be symmetrical initially however larger cysts may expand unilaterally
variable displacement of the bone
What are histological features of dentigerous cysts
epithelial lining
islands of odontogenic epithelium in the wall of the dentigerous cyst